This article investigates the microstructural evolution and mechanical integrity of austenitic stainless steel SS321, a titanium stabilized nuclear grade mainly preferred for severe corrosive environments. The double-sided gas tungsten arc welding (DS-GTAW) technique was utilized to fabricate the butt joint having a plate thickness of 6 mm. A heat input of 1.4058 kJ/mm was used to obtain the maximum depth of penetration (DoP) of 3.3 mm with welding speed 120 mm/min and current 220A. Optical microscopy reveals the microstructure of weldment and base metal (SS321). The DS-GTA weldments were subjected to tensile, bend, impact and microhardness tests and the results are evaluated. The fusion zone consists of columnar, equiaxed dendrites, and intermetallic compounds of Titanium carbide (TiC). From EBSD examination the higher fraction of Low Angle Grain Boundaries is corroborated to the increase in tensile strength and reduction in impact toughness of the weldment. The ferrite measurement reveals the increase in ferrite content in the weldment (6.1 FN) and this attributed to the presence of retained δ-ferrite in comparison to SS321 (1.2 FN). X-Ray Diffraction (XRD) pattern reveals austenite and ferrite peaks are present in the SS321 and weldment. Ductile mode of fracture (using SEM-Scanning electron microscope) was observed in the uni-axial tensile and impact test of weldment specimens.

本文研究了奥氏体不锈钢SS321的显微组织演变和机械完整性，奥氏体不锈钢SS321是钛稳定的核级，主要用于严酷的腐蚀环境。利用双面钨极电弧焊（DS-GTAW）技术来制造板厚为6mm的对接接头。使用1.4058 kJ / mm的热量输入，以120 mm / min的焊接速度和220A的电流获得3.3 mm的最大熔深（DoP）。光学显微镜揭示了焊件和贱金属（SS321）的微观结构。对DS-GTA焊件进行了拉伸，弯曲，冲击和显微硬度测试，并对结果进行了评估。熔合区由柱状，等轴枝晶和碳化钛（TiC）的金属间化合物组成。通过EBSD检查，证实了低角度晶界的较高比例与抗拉强度的增加和焊件冲击韧性的降低有关。铁素体测量显示出焊件中铁素体含量的增加（6.1 FN），这归因于与SS321（1.2 FN）相比，存在残留的δ-铁素体。X射线衍射（XRD）模式显示SS321和焊件中存在奥氏体和铁素体峰。在焊件试样的单轴拉伸和冲击试验中观察到了韧性断裂模式（使用SEM-扫描电子显微镜）。1 FN），这归因于与SS321（1.2 FN）相比，存在残留的δ铁氧体。X射线衍射（XRD）模式显示SS321和焊件中存在奥氏体和铁素体峰。在焊件试样的单轴拉伸和冲击试验中观察到了韧性断裂模式（使用SEM-扫描电子显微镜）。1 FN），这归因于与SS321（1.2 FN）相比，存在残留的δ铁氧体。X射线衍射（XRD）模式显示SS321和焊件中存在奥氏体和铁素体峰。在焊件试样的单轴拉伸和冲击试验中观察到了韧性断裂模式（使用SEM-扫描电子显微镜）。